1. Field of the Invention
The invention is directed to a vibration damper with variable damping force.
2. Description of the Prior Art
German reference DE 44 03 196 A1 describes, in FIGS. 3a to 3c, a vibration damper with variable damping force in which the extent of the change in the damping force depends on the spring deflection path. This is a matter of a load-dependent change in damping force which only functions in combination with a Macpherson strut or telescopic strut, since a vehicle suspension spring or stop buffer must work as an actuator. In compact vehicles, as a rule, there is a telescopic strut serving as a vibration damper. Mid- or upper-class vehicles, however, are frequently outfitted with vibration dampers constructed in the form of axle dampers. Accordingly, the vehicle suspension spring no longer works as an actuator for the load-dependent change in damping force.
Naturally, by way of alternative, an adjustable damping valve with electric control can be used, as is disclosed in FIG. 5 of the above reference. However, in vibration dampers of this constructional type there is a considerable expenditure on construction, especially with respect to safety in the event of system failure.